Generally, tap water (hard water) contains a large amount of chlorine used for water purification. In addition, due to factors, such as overage pipes or water pollution, tap water may contain various kinds of heavy metals (ions), such as iron, zinc, lead, mercury, etc. that have a negative influence on the human body. Although such tap water is not fatal to humans, when tap water directly contacts the skin of users, metal ions contained in water bond to fatty acids in soap and form metallic impurities. When such metallic impurities make contact with the skin of users they induce skin diseases, such as allergies, or promote skin aging.
To prevent these problems, various water softeners which change hard water into soft water using a method in which the calcium ions (Ca2+) and magnesium ions (Mg2+) of hard water are substituted for by sodium ions (Na+), have been developed and used mainly for washing.
To realize such an ion exchange process, the water softener is provided with a resin tank containing ion exchange resins made of high molecular compounds containing sodium ions (Na+), and a regeneration tank which contains ion exchange resin regeneration materials or regeneration agents, such as salt (NaCl) capable of producing sodium ions (Na+) when dissolved in water.
Hard water passes through the resin tanks during the ion exchange process of the water softener. A large amount of ball-shaped ion exchange resins are stored in the resin tanks, and water comes into contact with these ion exchange resins in the resin tank and soft water is produced. As the ion exchange process is repeated, sodium ingredients (Na+) are continuously removed from the ion exchange resins by continuous contact between the hard water and the ion exchange resins. Therefore, to regenerate sodium ingredients (Na+) of the ion exchange resins, regeneration water having NaCl components is supplied from the regeneration tank to the resin tank.
Typically, when a user is aware through a variety of methods that the amount of sodium ingredients (Na+) of the ion exchange resins has become reduced, the user makes the water softener start a regeneration process that supplies regeneration water. If the sodium ingredients of the ion exchange resins are successfully regenerated, the regeneration process can be terminated; however, it is difficult to clearly determine the appropriate regeneration process time.
To allow a user to determine the regeneration process time, in the related art, a gravity regenerated type water softener having a mechanical timer has been proposed. However, the water softener having the mechanical timer is problematic in that a user may not clearly know whether the current operation mode is regeneration mode or not. Further, even when the user knows that the current mode is regeneration mode, the user may not be aware of the remaining time for which regeneration should be executed.
In an effort to solve the problems, an electric timer or an electric signal controller may be provided in the water softener. However, the water softener is typically used in moist spaces, so that the electric timer or the electric signal controller may form a short circuit in the water softener and remarkably increase the production expenses of the water softener.
Further, the regeneration tank is typically provided with an openable cap for charging a regeneration agent into the tank. In the related art, raw water under pressure is contained in the regeneration tank, so that the interior of the regeneration tank is pressurized and it is difficult to open the cap because it is under pressure. Further, when the cap is opened, the cap may suddenly explode off due to the pressure and may injure a user.
To solve these problems, the conventional water pressure regenerated type water softener may be provided with a drain valve, which is opened to drain water from the regeneration tank and reduces the pressure inside the regeneration tank prior to opening the regeneration tank cap. However, the drain valve is typically located at a position that a user's hand cannot easily reach, thus being difficult to manipulate. Further, when a user carelessly opens the regeneration tank cap without opening the drain valve, the user may be injured by the exploding cap.
Further, the conventional water softener uses one resin tank, so that the water softener has a small size and may be easily installed in a desired place. However, when water at a temperature that was previously set by a user is supplied from a water tap to the water softener having one resin tank, the flow path of ion-exchanged soft water through which the soft water must pass prior to being distributed to the user is too long and an excessive amount of water stagnates in the flow path and does not move, so that an excessive amount of time is required to distribute the soft water at the temperature selected by the user.
In an effort to solve the problems, using two or more resin tanks in the water softener is possible. Although two or more resin tanks may realize easy control of the water temperature, they undesirably increase the size of the water softener, thus making installation of the water softener unfavorable.
Further, the conventional water softener does not allow a user to be aware of the total amount of distributed soft water, so that the user may not clearly determine the appropriate regeneration timing. To solve this problem, a flow sensor may be used in the water softener. However, the flow sensor may form an electric short circuit.
Further, in the related art, a water softener using an electric timer capable of producing an electric timer signal instead of a mechanical timer signal has been proposed. However, the water softener using the electric timer instead of the mechanical timer is problematic in that an electric short circuit may occur in the water softener because the water softener is typically used in moist environments as described above, and, further, the electric timer excessively increases the production cost of the water softener.